The diamond-like carbon layer (DLC layer) is excellent in wear resistance and lubricity, and is therefore used as a coating material for cutting tools, metal molds, and mechanical components. For example, Japanese Unexamined Patent Publication No. 2003-062706 (Patent Document 1) discloses that a DLC layer having a hydrogen content of 5% by atom or less is formed by ark ion plating method using argon gas as a carrier gas. Japanese Unexamined Patent Publication No. 2012-125923 (Patent Document 2) discloses a DLC coating containing argon deposited by a DC plasma CVD method. The DLC layers need improvement of wear resistance and improvement of weld resistance to a workpiece.